1

BioCoat™

Part 2. Pit-and-Fissure Sealant Incorporating SmartCap™ Technology

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Introduction

An estimated 23% of children 2 to 5 years-of-age and 56% of children 6 to 8 years-of-age in the United States have

dental caries in their primary dentition.1 Among adolescents 12 to 19 years-of-age and adults 20 to 64 years-of-age

in the United States, an estimated 58% and 91%, respectively, have experienced dental caries in their permanent

dentition.1,2 Caries experience for children from age 6 through adolescence is estimated at a worldwide average of

70%.3 Of significance for pit and fissure sealants, occlusal caries is estimated to represent 44% of all carious lesions

in primary molars and 80% to 90% in permanent posterior teeth.4 Pit-and-fissure sealants help prevent and arrest

dental caries by preventing cariogenic bacteria from accessing pits and fissures, and preventing bacteria already

present from accessing fermentable carbohydrates and metabolizing these to produce the acid that demineralizes

tooth structure as part of the caries process.4,5 Sealants may also help to lower salivary levels of cariogenic bacteria

(mutans streptococci) following placement in caries-free oral environments.6

Success rates

Caries reductions of 86%, 78.6% and 58.6% have been observed 1, 2 and 3 years, respectively, following resin-

based sealant placement.5 Sealants were found in one randomized trial to reduce the incidence of occlusal caries

in children and adolescents by 76% at 4 years post-placement on sound occlusal surfaces, with reapplication as

required.7 At 9 years, with no further reapplications, a caries reduction of 65% was observed.7 Caries reductions are

also observed when sealants are placed over incipient occlusal caries.8,9 In one meta-analysis of 6 studies comparing

caries progression of incipient (non-cavitated) caries lesions on occlusal surfaces, 2.6% of sealed surfaces progressed

(median annual percentage) versus 12.6% of unsealed surfaces.9 Sealants have also been found to be more effective

than fluoride varnishes for caries prevention on occlusal surfaces.7,10,11 Sealants should be monitored regularly after

placement and teeth should be resealed if necessary.

Current recommendations

The American Dental Association and the American Academy of Pediatric Dentistry issued joint recommendations

in 2016.5 These evidence-based recommendations support the use of pit-and-fissure sealants in primary and

permanent molars with sound or non-cavitated carious occlusal surfaces in children and adolescents.

Types of materials

Four types of sealant materials were considered, based on the evidence, when the recommendations

were formulated. Glass ionomer (GI) and resin-modified glass ionomer (RMGI) sealants contain a mix of

fluoroaluminosilicate glass and an aqueous polyacrylic acid solution. RMGIs additionally incorporate resin. GIs and

RMGIs set through an acid-base reaction, do not require acid-etching of the enamel, and adhere with formation

of a hybrid layer. They are moisture-tolerant, release high levels of fluoride, recharge with fluoride, and offer lower

2

shrinkage on setting and thermal expansion than resin-based sealants (RBS).12 However, they have a greater risk of

loss of retention, offer lower tensile strength, are more soluble and susceptible to desiccation. Compomers contain

resin material and are poly-acid modified. They are in effect hybrids between RBS and GI materials, offering some

characteristics of both.

RBS contain urethane dimethacrylate (UDMA) or bisphenol A-glycidyl methacrylate (bis-GMA) and fillers, require

acid etching of the occlusal surface adjacent to the pit/fissure prior to placement (and depending on the sealant,

also bonding), and set through polymerization.13 They are stronger than GIs and RGMIs, offer greater retention, less

expansion associated with water sorption, and have low susceptibility to drying. However, they are not moisture-

tolerant, release less or no fluoride and they do not have recharge capability. In addition, polymerization is a

potential source of shrinkage, albeit less than for bulkier resin-based materials.

Ideal properties

The success of sealants relies on their long-term durability. An intact seal prevents the ingress of cariogenic

bacteria and carbohydrates, microleakage and, subsequently, caries. Therefore, high tensile strength, compressive

strength, dimensional stability, wear resistance and lack of solubility in the oral environment are all important

physical properties of an ideal pit-and-fissure sealant. Flowability and adaptability must also be optimal for sealant

penetration and a lack of voids at the time of placement. The resulting surface should be smooth to help prevent

build-up of biofilm on and adjacent to the sealant. Moisture tolerance is also desirable in situations where a dry field

is difficult or impossible to achieve – e.g., a GI may be placed for a high caries risk patient while teeth are not yet

fully erupted. Ideal biochemical properties of sealants include sustained and controlled release of calcium, fluoride

and phosphate to help prevent demineralization and promote remineralization, and the ability to replenish these

ions are also desirable. Finally, the sealant must be biocompatible. (Table 1)

Table 1. Ideal physical and biochemical properties of pit-and-fissure sealants

Complete penetration of pits and fissures

Long-duration seal to enamel

Dimensional stability during and after placement

High shear bond strength (tensile strength)

High compressive strength

Wear resistance

Low solubility in presence of oral fluids and low pH

Moisture tolerance

Smooth surface

Sustained release of fluoride, calcium and phosphate ions

Ability to replenish fluoride, calcium and phosphate ions

Biocompatibility

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Properties of a novel resin-based sealant containing microcapsules

A new RBS, ‘BioCoat™ Bioactive Resin Pit and Fissure Sealant,’ contains microcapsules developed using SmartCap™

Technology. This technology results in distinct advantages in an RBS, due to incorporation of the microcapsules.

Controlled ion release, high enamel fluoride uptake, ion recharge, and high shear bond strength have all been

confirmed in laboratory studies on pit-and-fissure sealant formulations containing this novel technology.14-18

Ion release

Fluoride, calcium and phosphate ion release from RBS formulations containing microcapsules with aqueous

solutions of the respective salts has been demonstrated. In one laboratory study, microcapsules containing

an aqueous solution of 1) 0.8 molar sodium fluoride (NaF); 2) 5 molar calcium nitrate (Ca(NO3)2); or, 3) 6 molar

potassium phosphate (K2HPO4), were incorporated into commercially available sealants.19 Significant release of

fluoride, calcium and phosphate was observed for the respective formulations. Each release profile was performed

separately to show the accurate release of each ion. A fourth sealant was formulated containing three types of

microcapsules, each with one of three aqueous solutions (2% w/w 0.8 molar NaF, 2% 5 molar Ca(NO3)2 or 1% w/w 6

molar K2HPO4). Significant ion release was observed for all three ions from this sealant.19 (Figure 1) As a result, these

ions would be available to help prevent demineralization and to promote remineralization. Note that measurement

of fluoride release is suppressed by simultaneous release and complexing with calcium ions. It is also well-

recognized that all dental resin composite materials are porous to some degree.20 In addition, it is advantageous

that the microcapsules freely permit the movement of water into and through them, such that the structural

volume of the microcapsules remains essentially unchanged over time. The porosity of the resin material (substrate)

allows ions to move through in both directions: from the microcapsules to increase the concentration at the tooth-

material interface, and into the microcapsules to replenish ions from external sources (such as rinses or toothpastes).

Figures 1a-b.

A second study of a similar formula confirms sustained release of fluoride, calcium and phosphate ions for a sealant

formulation.24 Additionally, research confirmed ion release from experimental glaze formulations.21-23

Enamel Fluoride Uptake

Enamel fluoride uptake into demineralized enamel adjacent to an RBS was compared for three formulations: 1) 5%

Fluoride Release Profile from BioCoat™

0 days 7 days 31 days 180 days

0.25

0.2

0.15

0.1

0.05

0

pp

m/g

ram

FCalcium and Phosphate Release

Profile from BioCoat™ 2

31 days 180 days

6

5

4

3

2

1

0

pp

m/g

ram

4

w/w microcapsules with an aqueous solution of 0.8 molar NaF; 2) a mix of microcapsules each with either 2% w/w

with an aqueous solutions of 5 molar Ca(NO3)2, 2% with 0.8 molar NaF, and 1% w/w 6 molar K2HPO4; and, 3) A RBS

with no microcapsules, as a control.24 A modified method for measuring bioavailable fluoride (FDA Method 40)

was used for 12 sets of bovine enamel for each of the 3 formulations. Enamel samples were prepared, set in acrylic,

and placed in a demineralizing solution for 24 hours. Enamel fluoride and depth of etch were then evaluated. For

each specimen, the respective sealant was then placed on the acrylic surrounding the enamel (Figure 2), and the

specimens were soaked in nanopure water for 90 days before again measuring enamel fluoride and depth of etch.

Figure 2. Specimen design

Significantly greater decreases in depth of etch were observed for the formulations containing microcapsules,

demonstrating their remineralization potential.

Increases in enamel fluoride were significant for the formulations containing microcapsules and, in contrast,

negligible for the control sealant. Greater enamel fluoride uptake was also observed for the sealant containing the

mix of microcapsules. This suggests that the presence of calcium and phosphate increases enamel fluoride uptake

or precipitation of a protective fluoride-rich surface layer.24 (Figure 3)

Figure 3. Enamel fluoride uptake

Fluoride Uptake in Enamel After 90 DaysExposure to BioCoat™ (Modified Method )

BioCoatwithout SmartCap

Technology

BioCoat withfluoride ion

BioCoat withfluoride, calcium,

and phosphate ion

ug fl

uorid

e /g

of e

nam

el

0

50

100

150

200

5

Fluoride adsorption/absorption and recharge

The ability of a material to adsorb fluoride (onto its surface)/absorb fluoride (into the material) and to later release

this is advantageous for protection against dental caries. Fluoride released following its adsorption/absorption from

a fluoride toothpaste slurry (50% w/w toothpaste and 50% w/w water) was measured for a film of RBS material with

no microcapsules and for one with 7% w/w microcapsules containing only nanopure water.25 The film surface was

brushed for 2 minutes with 0.4 ml of the slurry, and this was repeated 40 times, each time with fresh toothpaste

slurry. (Figure 4) The samples were subsequently rinsed free of toothpaste slurry, dried and placed in nanopure

water. Samples of the fluid were taken over 2 weeks to measure its fluoride ion concentration to evaluate fluoride

ion release from the samples.

Figure 4. Brushing toothpaste slurry on the film surfaces

Significantly more fluoride was released from the sealant containing microcapsules, believed to be attributable to

the ability of the microcapsules (which previously only contained nanopure water) to incorporate fluoride.25 (Figure 5)

Figure 5. Evaluated fluoride ion release from sealant material with and without microcapsules

0 1 4 7

0.14

0.12

0.10

0.08

0.06

0.04

0.02

0

fluo

rid

e re

leas

e p

rofi

le (p

pm

/gra

m)

The Effect of Toothpaste Recharging on SmartCap™ Technology

BioCoat™ with SmartCap

Sealant without SmartCap

days

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Superior Shear Bond Strength for greater retention

Shear bond strength (SBS) has been compared for the BioCoat sealant and a leading commercially available RBS

(UltraSeal XT, Ultradent).26 Flat surfaces were prepared on extracted teeth, acid etched for 30 seconds, and then

rinsed with water for 10 seconds and dried. The respective sealant was then applied to the enamel surface and

light-cured for 30 seconds with a Spectrum 800 QTZ curing light (800 mW/cm2). After storing the specimens for

24 hours in distilled water at 37°C, SBS was measured using an Ultradent fixture with a notched chisel against and

parallel to the bonding sites. Each cylinder was placed under continuous loading at 1 mm/minute until fracture

occurred. SBS was significantly greater for the BioCoat sealant at 31.7 MPa (± 4.0) vs. 24.9 MPa (± 3.3) for the RBS

without microcapsules. The entirety of the formulation, including the microcapsules, small particle size and choice

of monomers contribute to the superior SBS compared to a leading pit and fissure sealant, which is advantageous

for durability.26 (Figure 6)

Figure 6. Shear bond strength (MPa)

The influence of toughening monomer content on shear bond strength

In earlier research, the influence of alternative toughening monomers on SBS was investigated for sealant

formulations containing microcapsules.27 Formulations with high, medium and low TEGMA content (41-55%, 31-40%

and 20-30%, respectively) and containing either bisGMA, UDMA or UMMA at the same ratios to the TEGMA were

evaluated. Glass and fumed silica levels as variables in the formulation were also investigated. As a result, more than

100 formulations were tested.27 (Table 2).

Shear Bond Strength (SBS) to Enamel*

BioCoat™ UltraSeal XT® plus

35

30

25

20

15

10

5

0

SBS

MPa

* Testing by Mark A. Latta, D.M.D., M.S., GL Materials LLC

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Table 2. Variables in the experimental pit-and-fissure sealant formulations

Toughening MonomerTEGMA Content (Defined as % of the Continuous Phase)

Glass Loading (Defined as w/w% of the formulation)

Fumed Silica Loading (Defined as w/w% of the formulation)

bisGMA High (41-55%) High (50-60 w/w%) High (2.1-3.0 w/w%)

UDMA Medium (31-40%) Medium (20-49 w/w%) Medium (1.1-2.0 w/w%)

UMMA Low (20-30%) Low (3-19 w/w%) Low (0.1-1.0 w/w%)

Flat surfaces were prepared on intact bovine teeth, and the surfaces were acid etched, rinsed with water and dried.

The respective sealant was applied to prepared flat surfaces of bovine enamel samples, which were then stored

for 7 days in distilled water at 37°C, before measuring SBS in the same manner as described above. When all other

variables were held constant (TEGMA content, glass loading and fumed silica loading), SBS was greatest for the

formulation containing bisGMA. (Figure 7)

Figure 7. Shear bond strength as a function of the toughening monomer

Filler Content

BioCoat pit and fissure sealant has a 56% filler content. A high level of filler increases compressive strength and wear

resistance, and lowers shrinkage. As a result, this formulation aids dimensional stability and long-term durability

by reducing the risk of loss of an intact seal and microleakage. The consistent small micron size filler improves

the movement of the sealant allowing for access into very tight areas and develops intimate contact with the

enamel. Furthermore, initial research on resin-based glaze formulations containing microcapsules, and with filler

loads ranging from 0% to 30%, confirmed that higher filler loading not only has no negative impact on ion release,

it results in greater ion release from the microcapsules.22 In addition, this novel sealant containing microcapsules

is thixotropic, flowing well into pits and fissures and adapting well to their configuration. This results in precise

adaptation, as confirmed in dye-penetration laboratory testing where no dye penetration was observed at the

sealant-enamel interface.28 (Figure 8)

Shear bond strength as a function of thetoughening monomer

0

5

10

15

20

25

bisGMA UDMA UMMA

Peak

Str

ess

(MPa

)

Toughening Monomer Used in the Formulation

8

Figure 8. Precise penetration and marginal adaption (dye-penetration laboratory testing)

Discussion

Existing pit-and-fissure sealants are effective in helping to control caries.29-32 Up until now, none of the materials

on the market have been able to meet all the requirements of an ideal sealant material. SmartCap Technology

has enabled the development of a novel RBS that incorporates microcapsules and offers distinct physical and

biochemical advantages compared with other RBS.

Fluoride release and replenishment of fluoride are potentially beneficial characteristics for pit-and-fissure sealants.

However, while there are studies on fluoride release from GI and RMGI materials, fluoride release from traditional

resin-based fluoride-releasing materials is less and there is no ability to recharge these (other than, possibly,

de minimus fluoride adsorption/absorption associated with their porosity). There is also a paucity of data on

the influence of monomers and fillers such as glass on the release of remineralizing ions (fluoride, calcium and

phosphate) from resin-based materials such as sealants.

In contrast, in vitro studies for resin-based formulations containing microcapsules developed using SmartCap

Technology, including sealants, have demonstrated significant remineralizing ion release and fluoride uptake into

adjacent enamel as well as significant fluoride charge/recharge capabilities.33 Laboratory studies have confirmed

their ability to release fluoride, calcium and phosphate ions in a controlled and sustained manner with the

potential to help prevent demineralization and to promote remineralization. In addition, ion release was shown in

other research to be influenced by the counterion, concentration, temperature, monomer component and filler

content.16,22,23,24 Through continual release of these ions, it is also possible to maintain a higher level of these ions

at the tooth surface compared to within the tooth structure, creating a concentration gradient. This discourages

loss of ions from the tooth and encourages the diffusion of these ions into tooth structure. In addition, it has

been demonstrated that fluoride recharge into the microcapsules can be achieved when brushing with a fluoride

toothpaste.

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The high filler content increases ion release and the influence of monomers is understood as a result of in vitro

studies. Studies have also confirmed that an RBS containing microcapsules and a high filler content offers excellent

penetration and marginal adaptation into pits and fissures through its thixotropic nature. Superior shear bond

strength compared to a leading resin-based pit-and-fissure sealant, as well as increases in fluoride, calcium and

phosphate release, while improving physical properties of the sealant were also confirmed.

Conclusions

Pit-and-fissure sealants have been shown in systematic reviews to be effective in preventing occlusal caries.

Nonetheless, to date the ideal sealant material has been elusive. SmartCap technology has enabled the

development of a novel RBS incorporating microcapsules loaded with bioavailable fluoride, calcium, and

phosphate ions. Research results are promising, and the ‘BioCoat™ Bioactive Resin Pit and Fissure Sealant’ offers

distinct properties that are unique and advantageous for a resin-based pit-and-fissure sealant.

References

1. Dye BA, Thornton-Evans G, Li X, Iafolla TJ. Dental caries and sealant prevalence in children and adolescents in

the United States, 2011–2012. CHS Data Brief, No. 191, March 2015.

2. Dye BA, Thornton-Evans G, Li X, Iafolla TJ. Dental caries and tooth loss in adults in the United States, 2011–2012.

NCHS Data Brief, No. 197, May 2015.

3. Beaglehole R, Benzian H, Crail J, Mackay J. The oral health atlas: Mapping a neglected global health issue. 1st Ed.

FDI World Dental Education & Myriad Editions, 2009.

4. Beauchamp J, Caufield PW, Crall JJ, et al. Evidence-based clinical recommendations for the use of pit-and-fissure

sealants: A report of the American Dental Association Council on Scientific Affairs. J Am Dent Assoc. 2008;139

(3):257-68.

5. Wright JT, Crall JJ, Fontana M, Gillette EJ, et al. Evidence-based clinical practice guideline for the use of pit-and-

fissure sealants. A report of the American Dental Association and the American Academy of Pediatric Dentistry.

J Am Dent Assoc. 2016;147(8):672-82. Available at: http://jada.ada.org/article/S0002-8177(16)30473-1/fulltext.

6. Baca P, Castillo AM, Bravo M et al. Mutans streptococci and lactobacilli in saliva after the application of fissure

sealants. Oper Dent. 2002;27(2):107-11.

7. Bravo M, Montero J, Bravo JJ et al. Sealant and fluoride varnish in caries: a randomized trial. J Dent Res.

2005;84(12):1138-43.

8. Fontana M, Platt JA, Eckert GJ, et al. Monitoring of caries lesion severity under sealants for 44 months. J Dent

Res. 2014;93(11):1070-75.

9. Griffin SO, Oong E, Kohn W, Vidakovic B, Gooch BF, Bader J, Clarkson J, Fontana MR, Meyer DM, Rozier RG,

Weintraub JA, Zero DT. The effectiveness of sealants in managing caries lesions. J Dent Res. 2008;87(2):169-174.

10

10. Hiiri A, Ahovuo-Saloranta A, Nordblad A, Mäkelä M. Pit and fissure sealants versus fluoride varnishes for

preventing dental decay in children and adolescents. Cochrane Database Syst Rev. 2010;(3):CD003067.

11. Splieth C, Forster M, Meyer G. Additional caries protection by sealing permanent first molars compared to

fluoride varnish applications in children with low caries prevalence: 2-year results. Eur J Paediatr Dent 2001;3:133-

12. Niederman R. Glass ionomer and resin-based fissure sealants - equally effective? Evid Based Dent. 2010;11(1):10.

13. Anusavice KJ, Shen C, Rawls RR. Phillips’ Science of Dental Materials. Missouri, US: Elsevier/Saunders; 2013.

14. Burbank B, Cooper R, Kava A, Hartjes J, McHale WA, Latta MA, Gross SM. Ion release and in vitro enamel fluoride

uptake measurements from sealants formulated with microencapsulated remineralizing agents. Am J Dent. 2017,

in press.

15. Burbank B, Slater M, Kava A, Doyle J, McHale WA, Latta MA, Gross SM. Ion release, fluoride charge, and adhesion

of orthodontic cement containing microcapsules. J Dent. 2016;45:32-8.

16. Falbo MA, Schmidt MQ, Greving TA, Davidson MT, McHale WA, Latta MA, Gross SM. The effect of counterion,

concentration, and temperature on the release of bioavailable calcium and phosphate ions from ion permeable

microcapsules for remineralization. [Chapter 16. In: Polymers for personal care and cosmetics; Patil A, et al.; ACS

Symposium Series; American Chemical Society: Washington, DC, 2013.]

17. Falbo M, Elassal P, Greving TA, McHale WA, Latta MA, Gross SM. The control of phosphate ion release from ion

permeable microcapsules formulated in to rosin varnish and resin glaze. Dent Mater. 2013;29:804-13.

18. Davidson MT, Greving TA, McHale WA, Latta MA, Gross SM. Ion permeable microcapsules for remineralization. J

Biomed Mater Res. Part A. 2012;100A:665-72.

19. Kava A, Burbank B, Valdman A, Zalsman B, Latta MA, McHale WA, Gross SM. Controlled release of

microencapsulated remineralizing agents from pit-and-fissure sealants. AADR, 2015, Boston, MA.

20. Rodrigues DS, Buciumeanu M, Martinelli AE, et al. Mechanical strength and wear of dental glass-ionomer and

resin composites affected by porosity and chemical composition. J Bio Tribo Corros. 2015;1:24.

21. Greving TA, Davidson MT, McHale WA, Latta MA, Gross SM. Release profiles of ion permeable microcapsules for

remineralization. AADR 2011, San Diego, CA.

22. Gross S, Fulton JC, Latta MA, McHale WA. Effect of glass filler on ion release from glaze formulations. IADR,

March 20-23, 2013. Seattle, WA.

23. Fulton JC, McHale WA, Latta MA, Gross S. Effect of MMA concentration on ion release from glaze formulations.

IADR, March 20-23, 2013. Seattle, WA.

24. Gross SM, Burbank B, Kava A, Valdman A, Zalsman B, Latta MA, McHale WA. Pit and fissure sealant with ion

permeable microcapsules promote fluoride uptake in enamel. AADR, 2015, Boston, MA.

25. Burbank B, Latta MA, McHale WA, Gross SM. Enhanced release of toothpaste originated fluoride from

microcapsule-containing dental materials. AADR, March 2015, Boston.

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26. Latta ML. In-vitro evaluation of shear bond strength to enamel of two pit and fissure sealants. Data on file.

27. Latta MA, Slater N, Bottros K, Gross SM, McHale WA. Effect of monomer on the flexural strength and SBS to

enamel of pit-and-fissure sealants formulated with microcapsules. AADR, March 2016, Los Angeles, CA.

28. Krämer N, Frankenberger R. Are newly introduced sealants suitable for preventive pit and fissure sealing?

Data on file.

29. Weintraub JA, Stearns SC, Rozier RG et al. Treatment outcomes and costs of dental sealants among children

enrolled in Medicaid. Am J Public Health. 2001;91:1877–81.

30. Ahovuo-Saloranta A, Forss H, Walsh T, Hiiri A, Nordblad A, Mäkelä M, Worthington HV. Sealants for preventing

dental decay in the permanent teeth. Cochrane Database Syst Rev. 2013;(3):CD001830.

31. Simonsen RJ, Neal RC. A review of the clinical application and performance of pit and fissure sealants. Aust Dent

J. 2011;56 Suppl 1:45-58.

32. Guler C, Yilmaz Y. A two-year clinical evaluation of glass ionomer and ormocer based fissure sealants. J Clin

Pediatr Dent. 2013;37(3):263-7.

33. Gross S, McHale W, Latta M, Zalsman B. Enamel fluoride uptake measurements from sealants formulated with

microencapsulated remineralizing agents. Caries Res. w015;49:297-369. 62nd ORCA Congress, July 1–4, 2015,

Brussels, Belgium, ORCA:137.

34. Schmidt MQ, Greving T, McHale W, Latta MA, Gross S. Temperature, concentration and counterion effect on ion

release from ion-permeable microcapsules. AADR Annual Meeting, March 21-24, 2012. Tampa, FL.

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